Widespread tropical deforestation and biodiversity loss in Southeast Asia due to the oil palm industry can be addressed by encouraging consumers to purchase sustainable palm oil (SPO). An online experiment was conducted to assess whether addressing barriers relating to education, motivation and product availability would increase purchasing of SPO. Australian adults (n = 628) were randomly assigned to either: (1) a newly developed interactive educational website on palm oil and SPO; (2) an existing educational video on SPO; or (3) an interactive website on differentiating between real and fake news (an attentional control condition). All participants completed pre-intervention and immediate post-intervention measures. Most participants (n = 403) completed follow-up measures two weeks later. Multivariate analysis revealed that the interactive website and educational video increased both knowledge and the intention to purchase SPO (compared to the attentional control), but neither significantly impacted follow-up self-reported SPO purchasing behaviour. Low perceived product availability might help explain the intention-behaviour gap. Our results suggest that, in addition to increasing consumer knowledge and motivation, promoting sustainable consumption requires creating opportunities for people to engage in the desired behaviour.